meeting 2025 04 29 n57 - JacobPilawa/TriaxSchwarzschild_wiki_5 GitHub Wiki

Context

  • We had discussed my preliminary nu10 calculation for H15 in our last meeting, and I've got some updates on a revised calculation. Specifically, I had combined the SuperCOSMOS Survey photometric data with the catalog of velocities from Durret+98.
  • I've now revised the calculation using the data from Agulli+17, a deep spectroscopic survey using VLT.
  • Note that for H15, there's an existing SDSS r band magntiude of 13.389, and an existing K_s_14arcsec = 11.741, giving an r-K color of ~1.648. I'll use this value for the color correction when computing nu10.

Diagnostics

  • First, here's a look at all sources in the catalog, along with some histograms of the velocities and G and R band magntiudes. I've included both the apparent magnitudes and the absolute magnitudes (computed from m - 5*log10(d_L) + 5).
    • I've also included a panel of the Mk magnitudes, computed assuming a r-K color of ~1.648, which is the r-K color of H15.
Sources Velocities and Magntiudes
  • The authors of the Agulli+17 paper then divide the galaxies into a red and blue sequence, which I've done as well here. Note that I am suspicious of the line of best fit formula they give in their paper. It seems like they might be rounding the slope and intercept, which is giving me ever-so-slightly different results, but it shouldn't matter too much at this level.
Red and Blue Sequence
  • And now here's the source map again, but this time colored by the red and blue sources, and zoomed into the H15 region with the 10 nearest neighbors highlighted.
Sources Zoomed to H15
  • And here's the data for these 10 nearest red sources. Note that the Mk column assumes an r-K color of 1.648 which is the r-K color of H15 itself according to NASA Extragalactic Database.
RAdeg DECdeg mr mg cz e_cz source Mr Mg g_r color_class separation_arcsec Mk
5 10.4644 -9.28722 18.81 19.56 17459 36 AF2 -18.1593 -17.4093 0.75 red 59.3535 -19.8073
6 10.4727 -9.29191 19.82 20.56 16577 66 VIMOS -17.1493 -16.4093 0.74 red 60.0223 -18.7973
7 10.451 -9.28422 15.12 16 15857 59 SDSS -21.8493 -20.9693 0.88 red 75.7853 -23.4973
8 10.4599 -9.32714 17.49 18.33 17804 45 SDSS -19.4793 -18.6393 0.84 red 86.2503 -21.1273
9 10.4774 -9.32084 17.76 18.57 15026 0 NED -19.2093 -18.3993 0.81 red 88.1892 -20.8573
10 10.462 -9.27831 19.83 20.59 17353 74 VIMOS -17.1393 -16.3793 0.76 red 89.7614 -18.7873
11 10.4383 -9.31916 18.52 19.3 17237 53 VIMOS -18.4493 -17.6693 0.78 red 96.6743 -20.0973
13 10.4622 -9.33454 18.85 19.67 17316 41 VIMOS -18.1193 -17.2993 0.82 red 113.114 -19.7673
14 10.4925 -9.29956 18.82 19.55 18251 59 VIMOS -18.1493 -17.4193 0.73 red 115.375 -19.7973
15 10.4908 -9.31533 17.47 18.25 15130 48 SDSS -19.4993 -18.7193 0.78 red 117.1 -21.1473
  • I then computed nu10 using the Mk column and the separation in arcsec (assuming an angular diameter distnace of 222.3 Mpc from Emily's paper), and here's how the new environmental plot looks with these updated numbers:
    • Note I've left it off the halo panel for now -- assembling those measurements like we talked about in the meeting yesterday and will update this afternoon!
Env

Slightly Revised Version Imposing Mk < -23.0

  • Note that the sources above consider the full catalog of galaxies without making any cuts on Mk. I ran the same calculation, this time only considering galaxies which have Mk < -23.0. When we limit ourselves to only galaxies with Mk < -23.0, the nu10 for H15 changes quite drastically, in large part because the separation to the 10th neighbor becomes very large (there are very few galaxes with Mk<-23.0).

  • Here are the 10 nearest sources which make the Mk cut:

Sources with Mk Cuts
  • And here's the information on these 10 sources:
RAdeg DECdeg mr mg cz e_cz source Mr Mg Mk g_r color_class separation_arcsec
7 10.451 -9.28422 15.12 16 15857 59 SDSS -21.8493 -20.9693 -23.4973 0.88 red 75.7853
20 10.4221 -9.31587 15.34 16.13 14261 52 SDSS -21.6293 -20.8393 -23.2773 0.79 red 142.826
24 10.4172 -9.30426 15.61 16.49 16825 0 NED -21.3593 -20.4793 -23.0073 0.88 red 152.715
68 10.3954 -9.36406 15.05 15.91 14500 38 VIMOS -21.9193 -21.0593 -23.5673 0.86 red 317.89
85 10.3768 -9.23519 15.09 16.01 16467 66 SDSS -21.8793 -20.9593 -23.5273 0.92 red 384.406
110 10.5782 -9.25791 15.58 16.51 16723 56 SDSS -21.3893 -20.4593 -23.0373 0.93 red 449.632
115 10.4591 -9.42985 14.68 15.58 17257 35 AF2 -22.2893 -21.3893 -23.9373 0.9 red 456.018
139 10.4292 -9.43943 14.39 15.27 16696 55 VIMOS -22.5793 -21.6993 -24.2273 0.88 red 502.705
175 10.3892 -9.1565 15.53 16.4 18152 48 SDSS -21.4393 -20.5693 -23.0873 0.87 red 585.206
227 10.4673 -9.50413 14.6 15.47 17764 39 VIMOS -22.3693 -21.4993 -24.0173 0.87 red 723.852
  • The nu10/nubar obtained from these galaxies is ~1020, compared to ~32651 when using the full set of galaxies.

Some revisions to the color correction

  • I was a little hasty with the color correction above and took a single r-K color for H15. This is likely a bad way to do this since H15 is likely quite a unique galaxy. I found Obric+06 which compiles colors ofr a very large sample of galaxies. In particular, their Figure 32 shows that the typical r-K value at z=0.05 is actually closer to ~2.8 rather than 1.6. If I revise my color correction to use 2.8, the resulting nu10/nubar=13758, and here are some diagnostics for that case:
    • Note that this extremely simple color correction seems to give us a reasonable approximation to the K-band magnitude for H15 listed in this work, which quotes MK = −26.76 compared to our MK = -26.48.
Magnitudes and Velocities Nearest 10
  • And here's a table with the galaxy data:
RAdeg DECdeg mr mg cz e_cz source Mr Mg Mk g_r color_class separation_arcsec
7 10.451 -9.28422 15.12 16 15857 59 SDSS -21.8493 -20.9693 -24.6493 0.88 red 75.7853
20 10.4221 -9.31587 15.34 16.13 14261 52 SDSS -21.6293 -20.8393 -24.4293 0.79 red 142.826
24 10.4172 -9.30426 15.61 16.49 16825 0 NED -21.3593 -20.4793 -24.1593 0.88 red 152.715
34 10.4702 -9.35841 16.72 17.57 18321 50 SDSS -20.2493 -19.3993 -23.0493 0.85 red 201.951
37 10.4009 -9.32508 16.15 17.03 16350 53 SDSS -20.8193 -19.9393 -23.6193 0.88 red 225.039
54 10.3947 -9.35006 15.94 16.83 17399 34 VIMOS -21.0293 -20.1393 -23.8293 0.89 red 287.559
62 10.445 -9.38692 15.79 16.7 17666 50 SDSS -21.1793 -20.2693 -23.9793 0.91 red 306.27
68 10.3954 -9.36406 15.05 15.91 14500 38 VIMOS -21.9193 -21.0593 -24.7193 0.86 red 317.89
70 10.3886 -9.24904 15.72 16.6 17561 49 SDSS -21.2493 -20.3693 -24.0493 0.88 red 320.429
79 10.4049 -9.22099 16.37 17.2 17603 47 SDSS -20.5993 -19.7693 -23.3993 0.83 red 355.137

Halo Information

  • Collecting some notes on the halo/total mass for H15 here.
Source Measurement Notes
Sanderson and Ponman+03 5.4e14 X-ray measurements (total mass = M/L * L) which also finds R200=28.1 arcmin
Rines and Diaferio+06 (r200,M200,Mproj,Mvir)=(1.02 h^{-1} Mpc, 2.5+/-1.19e14, 2.11+/-0.3e14, 2.94+/-0.29e14) this work actually quotes many different masses, including the same style of Mhalo as we are quoting in our work -- our work (in general) the projected mass estimate from Crook+07, which uses the Heisler and Bahcall projected mass estimator method.
Chen+07 8.08(+1.57)(-3.51)e14 total mass M500 at r500=(1.68)(+0.1)(-0.29) Mpc based on ROSAT and ASCA x-ray observations
Durret+05 4.3e14 (4.7e14 for isothermal profile) XMM Newton X-ray observations; the mass quoted is the total dynamical mass at the extent of their data (r=10 arcmin)
Habas+18 (r200,M200)=(1.73Mpc,6.1e14Msun) uses the Diaferio+99's caustic method, but mentions comparisons to Wen&Han+13, Durret+05, Sifon+15, Girardi which show a bit of tension
Wen&Han+13 TBD TBD
Sifon+15 TBD TBD
Girardi+97 TBD TBD
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